Houston's Air Quality: A Health Concern?

Houston, Texas, is a sprawling metropolitan area with a mix of industrial facilities and residential neighbourhoods. The city's approach to zoning has allowed industrial facilities to be located close to residential areas, exposing many residents to dangerous pollution levels. Houston's high average temperatures, abundant sunshine, large oil and gas industry, and dispersed population reliant on motor vehicles for transport all contribute to the city's air pollution levels. While Houston's annual air quality index (AQI) score has generally met the US Environmental Protection Agency (EPA) qualifications for good, there have been several unhealthy pollution days in recent years, particularly for sensitive groups such as children, the elderly, and people with pre-existing health conditions.

Houston's air quality index (AQI)

Houston's relatively high average temperatures, abundant sunshine, large oil and gas industry, and dispersed population reliant on motor vehicles for transport all contribute to the city's struggle to reach attainment levels. The American Lung Association's 2019 State of the Air report ranked Houston 9th in the nation for worst ozone pollution, with a weighted average of 22.3 days annually exceeding standards. The city has never met daily attainment levels for ozone, and other urban Texas cities like Dallas, Fort Worth, Austin, and San Antonio face similar issues.

Houston's air pollution has shown improvement over the last two decades, with the city's air quality now much better than that of Los Angeles, with which it once swapped "most polluted" titles. However, Houston has seen a recent rise in both PM2.5 and ozone pollution since 2017. From 2017 to 2018, Houston experienced a 7.8% increase in fine particulate matter, followed by an additional 11.3% increase from 2018 to 2019. These increases have been attributed to the city's growing population and economy.

PM2.5 pollution, which includes fine particulate matter measuring 2.5 micrograms or smaller in diameter, can penetrate deep into the lungs and bloodstream, leading to various short- and long-term health effects. Exposure to PM2.5 has been linked to conditions like heart and lung disease and early death. In 2019, Houston met the US EPA standard for annual PM2.5 exposure but exceeded the World Health Organization's more stringent standard. Certain months in 2019, such as November and December, experienced particle pollution levels defined as "moderate" air quality, which can pose risks to sensitive groups, including children, the elderly, and people with pre-existing health conditions.

Overall, while Houston's AQI has generally been rated as "good", the city continues to face challenges in maintaining healthy air quality levels, particularly regarding ozone and PM2.5 pollution. Real-time air quality data and forecasts are available for Houston residents to proactively reduce their exposure to unhealthy air.

Ozone pollution

Houston, Texas, has a problem with ozone pollution. In 2019, the city was ranked 9th in the country for worst ozone pollution, with an average of 22.3 days annually exceeding healthy standards. The city has never met daily attainment levels for ozone.

Houston's relatively high average temperatures, abundant sunshine, large oil and gas industry, and dispersed population reliant on motor vehicles for transport all contribute to the city's poor air quality. According to current models, more than 60% of ozone pollution is from cars. The city is trying to address this by encouraging the use of mass transit and the transition to fuel-efficient or low-emission vehicles.

In addition to vehicle emissions, industrial pollution from refineries, chemical plants, and other industrial operators near the Houston Ship Channel also contributes to high levels of air pollution in adjacent neighbourhoods, which are predominantly Latino.

The Environmental Protection Agency (EPA) has sought to list Houston as a "'severe' violator of 2008 federal ozone pollution standards", which would trigger more aggressive pollution controls in the region. This includes stricter air pollution permits, requiring businesses to install better pollution control technology, and requiring a greater reduction in pollution before approving new additional pollution sources.

Despite these efforts, Houston's air quality remains relatively poor compared to the US average, and the city has seen a recent rise in both PM2.5 and ozone pollution since 2017.

Fine particulate matter (PM2.5)

Fine particulate matter, or PM2.5, is one of the most damaging air pollutants and a serious threat to human health. These particles are minuscule, measuring 2.5 micrograms or smaller in diameter, and are often formed by the incomplete combustion of fossil fuels like coal, gas, and oil, as well as biomass fuels such as wood. Other sources include wildfires, road dust, construction sites, landfills, industrial sources, and pollen. Due to their tiny size, these particles can be inhaled and penetrate deep into the lungs and even enter the bloodstream.

In Houston, Texas, PM2.5 pollution has been a significant issue. While Houston's air quality has improved over the past two decades, it still has relatively high pollution levels compared to the US average. According to the 2019 World Air Quality Report, Houston ranked 244th out of 1517 cities for the highest PM2.5 levels in the United States. The city has also seen a recent increase in PM2.5 pollution since 2017, with an 11.3% increase from 2018 to 2019. This trend is concerning, and many attribute it to Houston's growing population and economy.

The health risks associated with PM2.5 exposure are significant. Studies have linked PM2.5 pollution to various adverse health effects, including respiratory infections and inflammation, heart disease, lung cancer, stroke, diabetes, asthma, low birth weight, IQ loss, and even premature death. In 2016, a study estimated that there were 8,405 premature deaths due to PM2.5 pollution in Texas, comprising 4.3% of all deaths in the state. In Harris County, for example, PM2.5 pollution was attributed to an estimated 1,520 new asthma cases, 122 non-fatal lung cancers, 355 strokes, and 3,470 new Alzheimer's cases in 2016.

To protect public health, the World Health Organization (WHO) has set a guideline for PM2.5 levels, recommending that they do not exceed 5 μg/m3. The US Environmental Protection Agency (EPA) has also set a standard of 12 μg/m3. In 2019, Houston met the EPA standard for annual PM2.5 exposure but exceeded the WHO guideline. However, it's important to note that annual averages may not always accurately represent potential risks, as there can be elevated periods of pollution. For instance, in November, December, and March of 2019, Houston experienced particle pollution levels defined as moderate by the US AQI, indicating some risk to sensitive groups such as children, the elderly, and people with pre-existing cardiovascular conditions.

Houston's industrial facilities and residential neighbourhoods

Houston, Texas, is a diverse and vibrant global metropolis with a large number of industrial facilities. The city is known as the "Energy Capital of the World" and is a headquarters hub for energy and healthcare, as well as life sciences, biotech, manufacturing, and aerospace industries. Houston's central location within the US and the Americas makes it an attractive industrial base with access to global markets. The city has four of the country's largest ports, two international airports, and a major highway and rail service, making it a dynamic hub for various industries.

Houston's industrial market is experiencing significant growth and resilience, with a strong demand and steady growth expected to continue. This growth is evident in the number of new developments and leases in the region. For instance, logistics companies like Grainger and Palmer Logistics have expanded their presence, with Grainger building a 1.2-million-square-foot distribution center in Hockley, and Palmer Logistics moving into a 616,700-square-foot warehouse facility in Baytown. Additionally, companies like Liberty Development Partners and Prologis are investing in industrial space, with plans to add millions of square feet of speculative and build-to-suit industrial space.

Houston's diverse and highly educated workforce also contributes to its industrial growth. The city has a large concentration of Fortune 500 company headquarters and a dynamic innovation ecosystem that nurtures startups across diverse industries. Houston's strategic location, robust infrastructure, and supportive community provide unparalleled opportunities for entrepreneurial success.

While Houston's industrial facilities drive economic growth, the city also recognizes the importance of residential neighbourhoods and quality of life for its citizens. The city has a unique cultural identity and offers a range of opportunities for individuals to thrive. Houston's residential areas benefit from the city's diverse population, talented workforce, and access to various industries.

However, one challenge Houston faces is maintaining healthy air quality for its residents. Houston's relatively high average temperatures, abundant sunshine, large oil and gas industry, and reliance on motor vehicles contribute to air pollution. According to the 2019 State of the Air report by the American Lung Association, Houston ranked 9th nationally for worst ozone pollution, with an average of 22.3 days annually exceeding standards. Despite meeting the US EPA's annual PM2.5 exposure standards in 2019, Houston exceeded the World Health Organization's more stringent standard. Certain months in 2019 experienced particle pollution levels that posed risks to sensitive groups, including children, the elderly, and people with pre-existing health conditions.

Air pollution in Houston's schools and childcare centres

Houston's air quality has been a persistent issue for the city, with its large oil and gas industry, high average temperatures, abundant sunshine, and dispersed population reliant on motor vehicles contributing to poor air quality. While the city's annual average air quality index (AQI) score has been deemed "good" by the US Environmental Protection Agency (EPA), indicating low health risks, there have been several unhealthy pollution days.

Houston's schools and childcare centres are not exempt from the city's air pollution issues. A study by the Environmental Defense Fund found that nearly half (46%) of the schools and childcare centres they monitored had elevated levels of nitrogen dioxide (NO2), a pollutant that can cause respiratory issues such as asthma and bronchitis. This is particularly concerning given that children are among the sensitive groups vulnerable to the effects of air pollution.

The study also revealed that Houston's lack of zoning places its schools and childcare centres in close proximity to sources of pollution. For example, 51% of the area's metal recycling facilities are located within half a mile of at least one school or childcare centre. This lack of zoning means that vulnerable individuals, including children, are exposed to harmful pollution.

To address these issues, city planners, communities, and public health officials can utilise air quality data, pollution source locations, and sociodemographic information to make informed decisions and implement targeted solutions. By prioritising the inspection and enforcement of major polluters, Houston can work towards reducing air pollution levels and protecting the health of its most vulnerable residents, including those attending schools and childcare centres.

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