Air Quality and Human Health
Air quality was not something that caught my attention until I moved to the city which scored 4th in the list of most polluted cities in the world (2017-2022). With a PM2.5 level of more than 10 times the WHO-recommended upper limit (5mcg/m3), the city inhabitants struggle with a number of health problems. The situation was worse in winters when the air would be visibly cloudy and would irritate your eyes and nose. I could hardly enjoy the winters in the open air.
The PM2.5 refers to particulate matter that are 2.5 microns or less in width. The reason why such particles are monitored for air quality is, particles below 5 microns are carried in the air for long distances and enter in the lower respiratory tract when inhaled. This is unlike droplets that are more than 5 microns in size which fall off to the ground quickly and get trapped in the upper respiratory tract when inhaled. In an analysis of 29 European cities, Antonis and colleagues found that an increase in PM10 by 10mcg/m3 was associated with 0.76% increase in cardiovascular deaths and 0.58% increase in respiratory deaths. The same increase in black smoke was associated with 0.62% and 0.84% increase respectively.1
Staying indoors with closed doors and windows, wearing masks, etc have been proposed as possible solutions. But I felt that HEPA filters which can filter out particles of size as small as 0.3 microns would make life easier and I bought an ‘air purifier’ in my residence (I believed ‘air purifier’ was useless and bogus until a few years before). Environment friendly measures such as separating industrial and residential areas and encouraging use of electric vehicles are more sustainable measures.
Living in less polluted coastal areas of the country has been blissful except for the distress it gives during the warm and humid summer months. A study from Australia found that the effect of heat on mental distress more than doubled when humidity reached the 99th percentile.2 Mite population and fungal growth are also enhanced by higher relative humidity. So here, de-humidifiers were to replace the ‘air-purifiers’!
Wherever be the geographic location, air quality needs to be taken care of in order to protect health and enhance productivity.
frAnalitis, Antonis*; Katsouyanni, Klea*; Dimakopoulou, Konstantina*; Samoli, Evangelia*; Nikoloulopoulos, Aristidis K.*; Petasakis, Yannis*; Touloumi, Giota*; Schwartz, Joel†; Anderson, Hugh Ross‡; Cambra, Koldo§; Forastiere, Francesco∥; Zmirou, Denis¶; Vonk, Judith M.**; Clancy, Luke††; Kriz, Bohumir‡‡; Bobvos, Janos§§; Pekkanen, Juha∥∥. Short-Term Effects of Ambient Particles on Cardiovascular and Respiratory Mortality. Epidemiology 17(2):p 230-233, March 2006. | DOI: 10.1097/01.ede.0000199439.57655.6b
Ding N, Berry HL, Bennett CM. The Importance of Humidity in the Relationship between Heat and Population Mental Health: Evidence from Australia. PLoS One. 2016 Oct 11;11(10):e0164190. doi: 10.1371/journal.pone.0164190. PMID: 27727320; PMCID: PMC5058549.