Reducing Hazardous Air Pollutants: Strategies For Cleaner Air

Hazardous air pollutants, also known as toxic air pollutants or air toxics, are substances that are known or suspected to cause cancer, birth defects, or other serious health issues. These pollutants can be gases, such as hydrogen chloride, or compounds and metals such as asbestos, cadmium, mercury, and chromium. The U.S. Environmental Protection Agency (EPA) has classified 188 pollutants as hazardous and is working with state, local, and tribal governments to reduce air emissions of these toxic air pollutants. The EPA has taken significant steps to reduce hazardous air pollutants and protect the health of Americans, including reducing toxic emissions from industrial sources and vehicles, addressing indoor air pollution, and setting stringent emission standards.

Regulate emissions from industrial sources

Regulating emissions from industrial sources is a crucial step in reducing hazardous air pollutants. The Clean Air Act, amended in 1990, mandates that the United States Environmental Protection Agency (EPA) take action to regulate hazardous air pollutants (HAPs), also known as air toxics, from large industrial facilities. This regulation occurs in two distinct phases.

The first phase of regulation is "technology-based." In this phase, the EPA establishes the Maximum Achievable Control Technology (MACT) standards for each industry group or "source category." These MACT standards are determined based on the emissions levels already achieved by the controlled and low-emitting sources within a particular industry. The EPA sets standards for controlling air toxic emissions, ensuring that industries adopt the most effective technologies available.

The second phase, which occurs within eight years of setting the MACT standards, is a "risk-based" approach called residual risk. During this phase, the EPA assesses the remaining health risks associated with each source category. The goal is to determine if the MACT standards adequately protect public health and the environment. If the existing standards are found to be insufficient, the EPA is required to implement more health-protective measures.

Since 1990, the EPA has issued regulations limiting toxic emissions from over 174 categories of major industrial sources. These include chemical plants, oil refineries, aerospace manufacturers, and steel mills. The EPA has also developed standards for smaller sources, known as area sources, such as gas stations and dry cleaners, which can have a significant cumulative impact on air quality, especially in heavily populated urban areas.

To further support communities, the EPA's area source program includes a community component. This component recognizes that some communities face disproportionate risks from toxic sources. It empowers local initiatives to reduce toxic sources more effectively and rapidly than through national regulations alone. The National Air Toxics Assessment (NATA) is a valuable tool that state, tribal, and local agencies, as well as communities, can use to evaluate potential pollutants and identify areas requiring further review.

Implement stringent emission standards for vehicles and engines

Hazardous air pollutants can be reduced by implementing stringent emission standards for vehicles and engines. The United States Environmental Protection Agency (EPA) has been working to reduce toxic emissions from vehicles and engines through new stringent emission standards and cleaner-burning gasoline. Here are some ways to implement stringent emission standards:

Regulatory Measures

The EPA has established progressively stringent emission standards for various pollutants, starting with carbon monoxide, hydrocarbons, and nitrogen oxides in the mid-1970s for on-road vehicles. In the early 1990s, similar standards were set for non-road engines and equipment. These standards set limits on the amount of pollution that can be emitted by vehicles and engines, and they have been updated over time to incorporate new technologies and improvements. For example, the EPA's Tier 3 vehicle and fuel standards, issued in 2014, aim to reduce emissions of air toxics from motor vehicles by 10 to 30% by 2030.

Collaboration and Technology

The road to clean air involves collaboration between the EPA, vehicle and engine manufacturers, fuel manufacturers, state and local governments, transportation planners, and citizens. Technological advances in vehicle and engine design, along with cleaner and higher-quality fuels, have significantly reduced emissions. Manufacturers have improved engine and vehicle technology by designing efficient combustion systems, introducing vapor recovery systems, using computer technologies for monitoring, and developing effective "after-treatment" technologies such as catalytic converters and particulate filters.

Compliance and Certification

The Clean Air Act (CAA) requires all engines and motor vehicles in the United States to meet emission standards and conformity requirements. Manufacturers must produce engines that meet the set standards, and anyone selling a vehicle in the US must demonstrate compliance with the CAA and EPA regulations. The EPA issues a Certificate of Conformity, which authorizes production and sales within the country. The certification process involves manufacturers providing detailed information to show that their vehicles meet the applicable requirements. This ensures that only compliant vehicles are sold and operated on public roads.

State-Level Standards

Under federal law, California is allowed to set more stringent vehicle emissions standards, and other states can choose to follow either the national or California standards. California's standards have influenced those of other states and even EU emissions standards due to the size of the state's market. Additionally, some states have areas that require emissions testing, while others do not, depending on the results of air quality tests.

International Standards

Different regions and countries have varying standards for vehicle emissions. While the US, Japan, and Europe have historically had their own sets of standards, newer markets like India, China, and South American countries have also started enforcing vehicle emissions standards. These standards are often derived from European requirements and aim to address the severe air quality problems caused by growing vehicle fleets. Internationally, there is a move towards adopting more stringent standards, such as Euro 6, to reduce air pollution from vehicles.

Address indoor air pollution

Ventilation

One of the most effective ways to improve indoor air quality is to increase ventilation. Opening windows and doors is an easy way to encourage a good exchange of indoor and outdoor air. Local exhaust fans in the kitchen and bathroom can also help to remove cooking fumes and steam, respectively, while also increasing the outdoor air ventilation rate. It is particularly important to increase ventilation during activities that generate high levels of pollutants, such as painting, cooking, or welding.

Air cleaners/filtration

Air cleaners can be an effective way to improve indoor air quality, particularly when used in conjunction with other methods. There are many types and sizes of air cleaners on the market, ranging from inexpensive table-top models to whole-house systems. However, air cleaners are generally not designed to remove gaseous pollutants, and their effectiveness depends on how well they collect pollutants and how much air they draw through the cleaning or filtering element.

Source control

Another strategy to improve indoor air quality is to eliminate individual sources of pollution or reduce their emissions. For example, sources containing asbestos can be sealed or enclosed, while gas stove emissions can be adjusted. In many cases, source control is a more cost-efficient approach than increasing ventilation, as increasing ventilation can also increase energy costs.

Other tips

• Ban smoking indoors.
• Keep pets out of bedrooms and bathe them regularly to reduce allergy-causing dander.
• Use a doormat to reduce pollutants carried into the house on shoes.
• Vacuum often, especially if you have pets.
• Minimize carpeting, as it can trap pollutants such as dust mites, pet dander, and mold spores.
• Use a dehumidifier and clean the filter regularly to reduce mold.
• Store chemicals, solvents, and pesticides away from living areas.

Reduce mobile source emissions

Mobile sources, such as cars, trucks, and construction equipment, are a significant contributor to hazardous air pollution. To reduce mobile source emissions, several regulations, programs, and initiatives have been implemented. Here are some detailed strategies to reduce emissions from mobile sources:

Regulations and Standards

The United States Environmental Protection Agency (EPA) has implemented various regulations and standards to reduce emissions from vehicles and engines, known as mobile source emissions. These include:

• Tier 3 Vehicle and Fuel Standards: These standards reduce emissions of air toxics from motor vehicles and provide more stringent gasoline sulfur standards, lowering sulfur content in gasoline.
• Tier 2 Motor Vehicle Emissions Standards: This program provides protective tailpipe emissions standards for all passenger vehicles while also reducing sulfur content in gasoline.
• Final Rule for Control of Hazardous Air Pollutants from Mobile Sources: This rule, finalized by the EPA in 2007, limits the benzene content of gasoline and reduces toxic emissions from passenger vehicles and gas cans.

Voluntary Programs

The EPA has also introduced several voluntary programs to reduce mobile source emissions:

• Clean Diesel: This program provides funding for projects that reduce harmful emissions from diesel engines, improving air quality and protecting human health.
• Clean School Bus USA: A national program aimed at helping communities reduce emissions from older diesel school buses.
• Ports Initiative: This initiative focuses on reducing air pollution, greenhouse gases, and improving air quality for communities near ports.
• SmartWay Program: Assists businesses in creating more sustainable supply chains by optimising freight transportation for fuel efficiency.

State-Specific Initiatives

In addition to federal regulations and programs, individual states like Vermont are implementing their own initiatives to reduce mobile source emissions:

• Low Emission Vehicle (LEV) Program: Vermont's LEV program, including Zero Emission Vehicle requirements, is a key strategy for mitigating climate change and maintaining air quality standards.
• Vehicle Emissions Inspection and Maintenance Program: This program ensures that Vermont vehicles maintain low emissions throughout their operational lifespan through annual testing and repairs.
• Automotive Technician Training Program: Provides training and information to automotive technicians to effectively maintain and repair vehicle emission control systems.
• Diesel Emissions Reduction Program: Offers technical support and funding for vehicle and equipment upgrades, retrofitting, and idling reduction technologies to reduce diesel emissions.

By implementing these regulations, programs, and initiatives, significant progress can be made in reducing mobile source emissions and improving air quality, ultimately protecting public health and the environment.

Develop community support initiatives

Community support initiatives are key to reducing hazardous air pollutants and their adverse health effects. Here are some strategies to develop such initiatives:

• Engage communities in addressing air quality issues: Communities, especially those disproportionately affected by air pollution, should be involved in identifying concerns and co-creating solutions. This can lead to improved environmental decision-making and a wider understanding of air quality issues and their health impacts.
• Promote diverse and inclusive participation: Ensure that community engagement initiatives are inclusive and representative of the local population, including diverse community members with technical skills and local expertise. This can lead to more effective solutions and increased community ownership.
• Provide education and training: Offer educational programmes and training opportunities to community members to increase their understanding of air pollution, its health impacts, and possible solutions. This can empower individuals to take action and make informed decisions.
• Facilitate community-led monitoring and assessment: Support community-led air quality monitoring and environmental/health assessments. Provide necessary equipment and training to community members to collect data and identify local pollution sources and health risks.
• Encourage local initiatives and policies: Encourage community-led initiatives and policies to reduce air pollution, such as no-idling policies for schools and daycares or programmes to reduce vehicle emissions. Provide resources and support to help communities develop and implement effective strategies.
• Address indoor air pollution: Promote initiatives to reduce indoor air pollution in homes, schools, and workplaces. Provide information and resources on best practices for ventilation, remodelling, pest control, and the use of non-toxic cleaning and art supplies.
• Foster partnerships and collaboration: Build partnerships between community members, researchers, and statutory organisations to address air quality issues effectively. Collaborate with local businesses, cities, nonprofits, and communities to develop and implement environmental programmes.

Frequently asked questions