Lisa Bramwell | Why should we care about the air we breathe?
Typically, when confronted by danger, we run to safety as we’ve perceived it with our senses. Air pollution, often nicknamed the silent killer, in many instances, doesn’t afford us such luxuries. Instead, we’re often left to deal with its impacts after either short- or long-term exposure to harmful substances in the air we breathe.
At least 16 per cent of our children in Jamaica are asthmatic. The prevalence of other associated respiratory disorders such as rhinitis and hay fever is also very high. According to the Ministry of Health (2018), non-communicable diseases (NCDs) are the leading cause of death in Jamaica. In fact, seven of every 10 deaths in Jamaica are attributed to four major NCDs – cancer, cardiovascular disease, diabetes, and chronic lower respiratory disease.
Exposure to particles has been identified as a causative factor for cardiovascular and circulatory disease as well as the onset of asthma.
WHERE ARE WE MOST EXPOSED?
We spend the majority of our time indoors. Some studies approximate this figure to 90 per cent of our day. The majority of that time, approximately 70 per cent, is spent within a residence with the remaining 20 per cent attributed to time spent within our workspaces, bars/restaurants, and other indoor locations. The relevance of the outdoors is significant, however, as on average, 60 per cent of the fine particles we inhale indoors originate from the outdoors.
Size is very important when considering particulate matter (PM). Health impacts from inhalation of PM in the air we breathe are directly related to the size of the actual particles inhaled. Particle size, in turn, is largely predicated by the source of the particle.
The most important sources of PM within the home are combustion processes, cooking and cleaning. Gas cooking generates ultrafine particles, while smoking, lighting candles, use of mosquito coils and incense burning, for example, are accountable for fine particles. Chores around the home such as folding clothes, sweeping, dusting, among others, are largely responsible for the large or coarse particles in the air we breathe.
The size of a coarse particle is typically 2 microns in diameter and larger. This is approximately 1/20 the diameter of a single strand of human hair. In comparison, an ultrafine particle is at most approximately 1/400 the diameter of a single strand of hair. Grains of pollen, a nuisance to many an asthmatic, are typically 50 microns in diameter, and therein lies the challenge of managing PM in the air we breathe. They are not visible to the naked eye, but their impacts can be substantial. It must be said that our homes do a lot to shield us from PM in the outdoor air, especially with respect to coarse and ultrafine particles. Fine particles, though, tend to accumulate in the indoors.
HEALTH IMPACTS OF EXPOSURES TO PM
Traditionally, persons have held the view that extended exposure to PM leads directly to the onset of asthma. Studies on both adults and children in recent years have proven that this is, in fact, the case, especially with respect to traffic-related air pollutants. Traffic-related air pollutants is the term used to collectively discuss oxides of nitrogen and sulphur, ozone and fine PM detected in proximity to high traffic areas. These chemicals have been implicated in both the worsening of asthma symptoms as well as the onset of new asthma cases.
What we may not be so familiar with is the relationship between PM and cardiovascular and circulatory health. Further, there also appears to be no safe exposure limit with respect to the development of cardiovascular and circulatory ailments.
Increased PM exposure within the home can lead to an inflammatory response in the lungs. The symptoms of inflamed lungs include, but are not limited to, pain in the chest and shoulders, shallow breathing, headaches, joint pain, and shortness of breath. This inflammatory response leads to the release of substances known as cytokines and biomolecules into the circulatory system. These actions precipitate the action of the autonomic nervous system and, ultimately, undesirable responses in our blood vessels, heart rhythms, heart variability and other behaviours beyond the scope of this paper. Ultimately, however, fine and ultrafine particles can enter the bloodstream and interact undesirably with blood cells and blood vessels.
The use of air filters has improved blood vessel function and reduced blood pressure provided PM concentrations within the air we breathe are less than five micrograms per cubic metre of air inhaled. The features within our home as well as the activities occurring in our homes, however, can largely influence our exposures to PM, and thus minimise harmful health impacts.
For persons highly desirous of preserving good indoor air quality within the home, air-quality monitors would be useful. Recording our daily activities while simultaneously monitoring PM levels, as well as perceived health ailments over time, would allow individuals to better manage their own exposure response cycle. Instruments such as the Speck, developed by researchers at the Carnegie Mellon University Robotics Institute, measure and record levels of fine PM in real time and data can be later extracted from the Web. Practical activities that reduce exposure include:
i. Reducing or eliminating smoking indoors.
ii. Limiting the burning of incense or similar materials within the home.
iii. Use varying mosquito repellent strategies. Don’t rely solely on coils, and discard all ashes derived from burning using moist cloths.
iv. Ensure that gas or electric stoves are located in well-ventilated areas. Preferably, they should be located some distance away from bedrooms or areas having high people traffic.
v. If possible, stoves should be fitted with extractor fans and HEPA filters to trap PM, and serviced regularly to ensure effectiveness.
vi. HVAC filters must be similarly serviced or cleaned as recommended.
vii. Keep tracked-in dirt to a minimum. Let’s leave our shoes at the door.
viii. Clean all hard floors, carpets, window sills, windows and areas where settled dust can accumulate frequently, using moist wipes to avoid unnecessary build-up. Always use appropriate personal protection, for example, a simple dust mask or a handkerchief securely fitted about the mouth and nose, if prone to allergic reactions.
ix. Vacuum carpets at least weekly. Steam vacuuming would be good at least twice yearly.
x. Clean pet areas daily and, if possible, place litter boxes in low-traffic rooms.
xi. Keep our four-legged friends who are frequently indoors well-groomed and clean.
We have within our reach the know-how to manage our exposures to PM and, therefore, I challenge us to take heed.
-Dr Lisa Bramwell is an associate professor in the Chemical Engineering Department at the University of Technology, Jamaica, and a certified air dispersion simulator using AERMOD. Email feedback to firstname.lastname@example.org.