Measuring air quality is inherently a measure of excess – any amount of toxic nitrogen oxides, ground-level ozone, and fine particles is likely bad for human health. But when it comes to federal regulation, the notion of excess is getting a bit wobbly. When a refinery or factory exceeds the limits set by local public health authorities to cap pollution, these fumes are considered “excess emissions” or, more surprisingly, “exceedances”.
The emission limits are of course arbitrary. Less pollution is always better in a country where more than 20 people die every hour because of poor air quality, and where that burden leans towards communities of color. But analyzing the human cost of these overflows is useful for weighing – or possibly tightening – these arbitrary limits. Nikolaos Zirogiannis, environmental economist at Indiana University, therefore decided to quantify the health toll of a state: how many people die each year because of it additional Pollution?
His team chose to focus on Texas, where the large number of fossil fuel and chemical plants combine with the state’s industry-friendly regulations to make it a hot spot for excessive emissions. But it also happens to have the most stringent public disclosure requirements in the country; in 2001, state legislators not only required facilities to report excess emissions within 24 hours, but that this data be updated daily for public review. “Texas is the only state in the country that has a very, very detailed record-keeping requirement in place for these types of shows,” Zirogiannis says.
He and his team combed through 15 years of reports, along with mortality statistics and data from local air quality monitors. They concluded that each year 35 elderly people die in Texas as a result of these excessive emissions – in other words, these are deaths that would not have happened if all polluters had stayed within the allowable limits. This is the first time that a scientist has associated health effects with this subset of pollution. The results will appear in the July issue of Journal of Environmental Economics and Management.
“It’s a very high number,” says Zirogiannis, “because it’s a number that comes solely from these overruns.”
The main way the team linked these emissions to fatalities was to isolate the degree to which they increase local levels of ground-level ozone, a nasty pollutant that can trigger heart problems and flare-ups of respiratory disease. “There is an abundant literature linking high ozone levels to respiratory and cardiovascular mortality,” says Joan Casey, an environmental health scientist at Columbia University who was not involved in the study. Heart attacks, strokes, asthma attacks, exacerbation of chronic obstructive pulmonary disease – “these are the types of results I would expect that explain what they’re seeing here,” Casey says.
Oil refineries, natural gas plants, chemical plants, power plants and pipelines are hardly closed systems. Anytime a person stops for maintenance, restarts, or just happens in the event of a malfunction, this is an unusual emissions opportunity. Nitrogen oxides, carbon monoxide, volatile organic compounds (VOCs) or other pollutants are released into the local air. Each can be inherently dangerous, but in a sunny atmosphere these chemicals also contribute to the formation of ground-level ozone.
The team linked industrial air pollution to peaks in local ozone levels by collecting reports from the Texas Commission on Environmental Quality for the years 2002 to 2017. These data showed when, where and why the releases were made, and what type of chemical pollution was involved. They found a correlation between the release of nitrogen oxides, carbon monoxide, and VOCs with jumps in ozone readings from monitors. followed by the Environmental Protection Agency.