Clean air conditions in lockdown led to a reduction in hospital visits for Oxford residents with asthma, a new study has found.
The OxAria study team working in the city of Oxford found that reductions in nitrogen dioxide and particulate matter combined with fine weather during the 2020 Covid-19 lockdowns led to a 41 per cent reduction in adult asthma hospital stays compared to the previous five-year average.
The findings published in BMJ Open help better understand how demand for NHS inpatient care may change when air quality is improved and highlight how large-scale measures to improve air quality can protect vulnerable people living with chronic asthma in urban areas.
Elevated levels of nitrogen dioxide, particulate matter 2.5 (PM2.5) and particulate matter 10 (PM10) contribute towards many conditions, including heart disease, chronic lung disease, cancers and preterm births.
The researchers, led by the University of Birmingham, analysed the link between acute asthma hospital admissions and specific air pollutant levels in four city centre postcodes in Oxford during 2020. During this time, there were two national Covid-19 lockdowns between March-June and November-December, and levels of air pollutants fell when compared to average values for the previous five-year period. Nitrogen dioxide levels dropped by 26.7 per cent, levels of PM 2.5 by 33.5 per cent and PM 10 by 18.6 per cent in Oxford.
Falling pollution levels strongly correlated with reduced hospital admissions for asthma patients within the study area. Across the four postcodes, acute asthma care provision for adult residents decreased from 78 per 100k residents in 2015-19, to 46 per 100k residents.
Dr Suzanne Bartington, from the University of Birmingham and lead author of the study, said: ‘The impact of lockdowns on reductions in traffic and industry led to a unique situation where air quality significantly improved for a temporary period during the Covid-19 pandemic. The results of air pollution levels falling may have had an impact on the number of severe asthma cases that need acute hospital care, with 41 per cent fewer hospital stays compared to the previous five-year average.’
The researchers also identified a four per cent increase in risk of asthma hospital admissions for every 1 μg/m3 increase in mean monthly nitrogen dioxide and an approximately three per cent increase in risk for every 1 μg/m3 increase in mean monthly PM2.5 levels, highlighting the link between ambient nitrogen dioxide and PM2.5 air pollution exposure and increased the risk of asthma admissions.
Dr Bartington added: ‘This is an important study to help us better understand how demand for NHS inpatient care may change when air quality is improved. Whereas previous studies on lockdown air pollution have focused on major cities in the UK such as London or Birmingham, Oxford is more typical of a smaller city or large town where many residents live.’