UK COVID-19 lockdown: 100 days of air pollution reduction?

Abstract

On the 23 March 2020, a country-wide COVID-19 lockdown was imposed on the UK. The following 100 days saw anthropogenic movements quickly halt, before slowly easing back to a “new” normality. In this short communication, we use data from official UK air-quality sensors (DEFRA AURN) and the UK Met Office stations to show how lockdown measures affected air quality in the UK. We compare the 100 days post-lockdown (23 March to 30 June 2020) with the same period from the previous 7 years. We find, as shown in numerous studies of other countries, the nitrogen oxides levels across the country dropped substantially (∼ 50%). However, we also find the ozone levels increased (∼ 10%), and the levels of sulphur dioxide more than doubled across the country. These changes, driven by a complex balance in the air chemistry near the surface, may reflect the influence of low humidity as suggested by Met Office data, and potentially, the reduction of nitrogen oxides and their interactions with multiple pollutants.

Regional Scale Impact of the COVID-19 Lockdown on Air Quality: Gaseous Pollutants in the Po Valley, Northern Italy

“…However, a certain decrease in concentration levels appeared at the end of February, when the lockdown was already enforced in small municipalities in the middle of the Po Valley. Conversely, in March and April, they were always below q2 [14][15][16][17][18][19] (<30 µg m −3 ), and even below q1 [14][15][16][17][18][19] (<15 µg m −3 ) in 50% of the days, with the differences between mean values usually being in the 5−10 µg m −3 range, but occasionally as high as 12-15 µg m −3 . Maximum daily values of 2020 were practically always lower than in the past, lying in the q3 14-19 -max 14-19 range, and even within the IQR 14-19 sometimes, with values getting closer and closer to q3 14-19 , down to around 30-40 µg m −3 , in late April.…”

“…For time pattern analyses at the monthly level, data distributions for each single calendar day were assembled, assessing the frequency of occurrence of 2020 data within corresponding concentration ranges observed in the previous six years. These ranges were defined based on the q1 14-19 , q2 [14][15][16][17][18][19] , and q3 [14][15][16][17][18][19] values, respectively representing the 1st, 2nd, and 3rd quartiles computed for the 2014-2019 daily datasets. The interquartile range IQR 14-19 (i.e., the concentration interval between the third and the first quartile, q3 14-19 -q1 [14][15][16][17][18][19] ) was also used for the assessment.…”

“…Daily means were at least 10 µg m -3 lower than the average of the previous Table 3. Frequency distribution (fractional number of days in each month) of the 2020 overall daily mean NO 2 concentrations by concentration range observed for the 2014-2019 period (q1 14-19 , q2 [14][15][16][17][18][19] , and q3 [14][15][16][17][18][19] : 1st, 2nd, and 3rd quartiles). The stratified analyses of the time patterns give further evidence to the piece of information obtained from monthly averaged data, namely, as far as the difference between traffic and background stations is concerned.…”

“…Recently, a number of papers have been published reporting the changes in concentration levels for certain pollutants in different areas worldwide, where light or heavy restrictive measures have been implemented [5]. Most of these works refer to China [6][7][8], Korea [9][10][11], India [12], Central [13,14], and South-East Asia [15], but also to Western European countries [16][17][18], Africa [19,20], and North and South America [21][22][23]. The few studies related waste treatment each accounted for 1% of the total annual emissions (about 185 Gg year -1 ).…”

Can COVID-19 and environmental research in developing countries support these countries to meet the environmental challenges induced by the pandemic?

“…Comparing the air quality index of the unblocked cities and the blocked cities, it was found that the daily air quality index and PM 2.5 of the blocked cities dropped by 19.84 points (17%) and 14.07 μg m −3 (17%), and after the city blockade, the quantity indicators of CO, SO 2 , NO 2 , and O 3 are significantly reduced (He, Pan, & Tanaka). Compared with the concentration of nitric oxide (NO) in the past 7 years, the concentration of NO in the UK this year has decreased by approximately 61% (Higham et al 2021 ). During the COVID-19 virus epidemic, the prevention and control policies of various countries and regions reduced the concentration of air pollutants worldwide, optimized air quality indicators, and improved air quality conditions.…”