It might seem reasonable to think air pollution is only a problem when the sky is thick with brown smog. But a new study is further proof the problem starts much earlier – and well below the minimum air-quality standards.
Worse, the research shows the negative effects increase most rapidly at lower levels of exposure. And they hit poorer people hardest.
The policy implications of these findings are critical: there is no safe amount of air pollution. Treating reference standards as a licence to pollute up to those concentrations and a free pass to allow continued emissions below those concentrations cannot be accepted based on the current evidence. Air-pollution regulations, such as those in the United States, do not provide enough protection from worsening symptoms of asthma, according to a 2022 US study on the relationship between pollution levels and asthma-related hospitalisations for people on Medicaid. Described by the study’s researchers as “the most disadvantaged population in the United States”, Medicaid recipients include people on very low incomes, people with disabilities and people aged over 65. The study investigated the exposure–response relationship between exposure to pollutants and people’s health response. It found increased concentrations of nitrogen dioxide and fine particulate matter were associated with an increased risk of hospitalisation for asthma over the following six days after exposure. Importantly, the study showed that the increased risk of hospitalisation for each unit increase in pollutant exposure was greatest for those people whose exposure levels were well below the existing US minimum air-quality standard. In general, the effect was the same regardless of differences in individual characteristics, except it was stronger in people who had only had a single admission to hospital than in those with multiple previous admissions.
