How Do Laws Control Particulate Matter Pollution?

Particulate matter (PM) is a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be visible, while others are so small they can only be detected using an electron microscope. PM is known to cause serious health issues, including respiratory and cardiovascular illness, and can even increase the risk of adverse birth outcomes, psychiatric disorders, and Alzheimer's disease. To combat this, the Clean Air Act requires the Environmental Protection Agency (EPA) to set national air quality standards and periodically review and update them to ensure adequate health and environmental protection. The EPA has implemented rules and programs to reduce emissions of pollutants that form PM, helping state and local governments meet the national air quality standards. These include the General Conformity Rule, the Visibility and Regional Haze Rule, and voluntary programs like BurnWise and Clean Diesel. Additionally, the EPA's new air pollution rules have restricted the amount of fine particulate matter released into the air, aiming to prevent premature deaths and improve overall air quality.

The Clean Air Act and EPA standards

The Clean Air Act (CAA) is a comprehensive federal law that regulates air emissions from stationary and mobile sources. It authorises the Environmental Protection Agency (EPA) to establish National Ambient Air Quality Standards (NAAQS) to protect public health and welfare and to regulate emissions of hazardous air pollutants. The EPA's Clean Air Markets Division (CAMD) runs programs that reduce air pollution from power plants, addressing environmental issues such as particle pollution.

The Clean Air Act requires the EPA to set national air quality standards for particulate matter, as it is one of the six criteria pollutants considered harmful to public health and the environment. The EPA must also periodically review and update these standards to ensure adequate health and environmental protection.

Section 112 of the Clean Air Act specifically addresses emissions of hazardous air pollutants. The 1990 amendments to this section require the issuance of technology-based standards for "major sources" and certain "area sources". Major sources are stationary sources that emit or have the potential to emit 10 tons or more of a hazardous air pollutant per year. These emission standards are referred to as "maximum achievable control technology" or "MACT" standards.

The Clean Air Act also regulates air pollution from mobile sources, including motor vehicles and nonroad engines. This includes regulating vehicle emission limits for hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), and particulates in the case of diesel vehicles.

In addition to federal regulations, states like Illinois have their own Environmental Protection Acts, which prohibit the discharge or emission of any contaminant that may cause air pollution. This includes fugitive particulate matter, which is defined as emissions that are visible beyond the property line of the emission source.

State-level legislation: Illinois and Colorado

In Illinois, the Illinois Environmental Protection Act, Section 9(a) states:

> "No person shall cause or threaten to allow the discharge or emission of any contaminant into the environment in any State so as to cause or tend to cause air pollution in Illinois, either alone or in combination with contaminants from other sources, or so as to violate regulations or standards adopted by the Board under this Act."

The 35 Illinois Administrative Code 212.301 - Fugitive Particulate Matter, states:

> "No person shall cause or allow the emission of fugitive particulate matter from any process including any material handling or storage activity, that is visible by an observer looking generally toward the zenith at a point beyond the property line of the emission source."

The Illinois Pollution Control Board is the state's environmental court and rule-making body for pollution cases. The Board hears and decides on environmental enforcement actions, but does not prosecute or investigate alleged pollution. Any person can file a complaint with the Board against an alleged polluter, which can be either informal or formal. The Illinois Attorney General's Environmental Enforcement Division handles civil environmental litigation and has over 25 attorneys working across the state to protect the environment.

In Colorado, the Department of Public Health and Environment implements federal standards through permitting emission sources, enforcement, and compliance. The Clean Air Act provides the EPA with the authority to reduce air toxic emissions through modifying fuel requirements and issuing periodic updates to more comprehensive, multi-pollutant approaches. In recent years, Colorado has passed state-specific air toxics legislation to complement federal requirements. The Air Pollution Control Division monitors air toxics in the state, and HB22-1244 (Public Protections From Toxic Air Contaminants) was signed into law in June 2022. This law creates reporting and ambient air monitoring requirements for air toxics. The Air Quality Control Commission has also adopted regulations for the control of particulate matter, smoke, carbon monoxide, and sulfur oxides.

Sources of particulate matter

Particulate matter (PM) is a type of air pollution consisting of a complex mixture of solids and aerosols composed of small droplets of liquid, dry solid fragments, and solid cores with liquid coatings. These particles vary widely in size, shape, and chemical composition and may contain inorganic ions, metallic compounds, elemental carbon, organic compounds, and compounds from the earth's crust.

PM is classified based on particle size, with PM2.5 referring to fine particles with diameters of 2.5 micrometers or smaller, and PM10 referring to inhalable coarse particles with diameters between 2.5 and 10 micrometers. These particles can be emitted directly from sources or formed in the atmosphere through chemical reactions.

Outdoor sources of PM include vehicle exhaust, burning wood, gas and other fuels, wildfires, industrial activities, construction sites, unpaved roads, agricultural fields, and natural sources such as pollen and sea spray. Indoor sources of PM include cooking, cleaning, burning candles or incense, tobacco smoke, and biological sources such as pollen, mold spores, and dust mites.

PM2.5 particles are of particular concern due to their potential to cause serious health issues. They can penetrate deep into the respiratory tract, reaching the lungs, and have been linked to increased cardiovascular and respiratory hospital admissions, worsening of respiratory diseases, and adverse effects on heart and lung function.

Over the years, efforts have been made to reduce particulate matter emissions, with notable decreases in PM2.5 and PM10 emissions in certain regions. However, it is important to continuously monitor and regulate these emissions to improve air quality and protect public health.

Health impacts of particulate matter

Particulate matter, also known as particle pollution or soot, is a mix of tiny solid and liquid particles in the air. The size of these particles is directly linked to their potential for causing health issues. Small particles, especially those less than 10 micrometres in diameter, are of significant concern as they can infiltrate deep into the lungs, and some may even enter the bloodstream.

The health effects of particulate matter are far-reaching and have been observed in both indoor and outdoor environments. Particle pollution is associated with increased mortality, particularly from cardiovascular and respiratory diseases. It can cause a range of adverse health effects, including eye, nose, throat, and lung irritation, coughing, sneezing, a runny nose, and shortness of breath. Those with existing heart or lung conditions, pregnant women, children, older adults, minority populations, and low socioeconomic groups are particularly vulnerable to the impacts of particle pollution. Scientific studies have found a correlation between daily PM2.5 exposure and higher hospital admissions, emergency department visits, and deaths.

Long-term exposure to fine particles has been linked to increased mortality from heart disease and may contribute to higher rates of chronic bronchitis, reduced lung function, and lung cancer. The sources of particulate matter are diverse, including vehicle emissions, burning wood, wildfires, industrial emissions, and household activities such as cooking with gas or burning candles.

To protect against the health impacts of particulate matter, individuals can monitor air quality and limit their exposure to particle pollution, especially during periods of poor air quality. The use of face masks, such as N95 or KN95 masks, can provide protection when spending time outdoors in areas with elevated particle pollution levels. Adjustments to work schedules and increased time spent indoors can also help reduce exposure.

It is important to note that there is no safe threshold for breathing in fine particles, and the health effects of particulate matter are a significant concern for policymakers and researchers. Strategies to reduce air pollution and mitigate its health impacts are crucial to safeguard public health and improve air quality.

Monitoring and forecasting air quality

One of the key tools for monitoring air quality is ambient air monitoring, which involves the systematic, long-term assessment of pollutant levels. This includes measuring the quantity and types of pollutants in the outdoor air. Monitoring stations are strategically placed near busy roads, in city centers, or at specific locations of concern, such as schools and hospitals. These stations are essential for supporting human health objectives and are often operated by tribal, state, or local governments in collaboration with the EPA.

The EPA also works closely with technology developers, air quality managers, citizen scientists, and the public to advance air sensor technology. Low-cost, portable air sensor monitors are now widely used across the United States to understand air quality conditions at a community level. The EPA provides guidance on the performance, operation, and best practices for using these sensors, empowering individuals to take an active role in monitoring their local air quality.

Additionally, forecasting air quality involves the scientific prediction of pollution concentration in the atmosphere for specific locations and times. Organizations like the Office of Air Quality in Indiana produce daily SmogWatch forecasts and issue Air Quality Action Day (AQAD) advisories when levels of ozone or fine particulate matter are expected to be unhealthy. This information is crucial for vulnerable groups, such as children and the elderly, to take necessary precautions.

Local, state, and regional partners also play a significant role in air quality forecasting. For example, the Louisville, Kentucky Air Pollution Control District implements the Federal Clean Air Act and collaborates with the U.S. EPA and neighboring states to improve air quality in their region. By combining meteorological data with air quality expertise, these partnerships enable more accurate forecasting and the development of effective strategies to mitigate particulate matter pollution.

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