Climate change is expected to affect air quality through several pathways, including production of allergens and increase regional concentrations of ozone, fine particles, and dust. Some of these pollutants can directly cause respiratory disease or exacerbate existing conditions in susceptible populations, such as children or the elderly. US President Obama said on ABC’s “Good Morning America” cited his daughter Malia’s childhood asthma as an example of the harmful effects of climate change.
Warming temperatures in some areas, like the northern United States, extend the periods during which plants release pollen. The combined effect of warming temperatures and more CO2 means that the amount of pollen in the air has been increasing and will continue to increase as climate change worsens.
The manifestations of allergy—sneezing, wheezing, itching, and rashes—are signs of an immune system running amok, attacking foreign invaders that normally mean no harm. Allergens include pollen, dust mites, mold, food, latex, drugs, stinging insects, or any of the other oddball substances to which the body will react. This is because some people’s immune systems recognize the protein sequence in pollen, for instance, as similar to the protein sequence in parasites. When this happens, their bodies attempt to expel the “parasite” through sneezing and other symptoms.
Asthma is a big contributor to keeping allergists in business. This chronic inflammation that causes airways to constrict affects about 20 million Americans, twice as many as 20 years ago. About 4,000 die each year. It is the most common chronic disease of childhood but affects more adults than children. It is characterized by repeated episodes of coughing, wheezing, chest tightness, breathlessness causing almost 2 million emergency room visits, 5 million hospitalizations, 3,630 deaths and cost $56 billion per year in US (2007).
In Hong Kong, according to data from the Census Department in 2011, more than 330,000 people suffering from asthma. Every year, Hong Kong has about 70 to 90 deaths caused by asthma attacks; among them, 20 to 30 people passed away in their prime (aged between 15 and 44).
There are little epidemiological data on asthma and allergy in Hong Kong adults. In a review of data from local public hospitals in 2005, asthma ranked fourth and fifth highest as a cause of respiratory hospitalizations (5.7%) and respiratory inpatient bed-days (2.6%), respectively. The overall crude hospitalization rate for asthma in 2005 was 76/100 000, and was high at both extremes of age. The age-standardized mortality rate of asthma increased between 1997 (1.33/100 000) and 1998 (1.82/100 000), but decreased thereafter to 1.4/100 000 in 2005. The overall annual change in asthma mortality was not significantly different between 1997 and 2005. The prevalence of current wheeze increased from 7.5% in 1991/1992 to 12.1% in 2003/2004 among people older than 70 years; the corresponding figures for asthma were 5.1% and 5.8%.
There is a substantial connection between allergies and asthma. The risk factors for allergies and asthma are more severe in vulnerable communities where conditions for good health may be compromised and where environmental risks are at stake. Many people think of asthma and allergies as two completely different things. Both have symptoms that can include persistent coughing, but for the most part, asthma is thought of as a serious condition that requires regular treatment. What many people don’t realize is that allergies can actually, over time, trigger asthma symptoms.
September is usually the month when carbon dioxide is at its lowest after a summer of plants growing and sucking it up in the northern hemisphere. As fall wears on, those plants lose their leaves, which in turn decompose, releasing the stored carbon dioxide back into the atmosphere. It was reported, however, that 2016 will be the year that carbon dioxide officially passed the symbolic 400 ppm mark, never to return below it in our lifetimes. Even if the world stopped emitting carbon dioxide tomorrow, what has already put in the atmosphere will linger for many decades to come. This year, in addition to marking the start of our new 400 ppm world, is also set to be the hottest year on record. The planet has edged right up against the 1.5oC (2.7oF) warming threshold, a key metric in last year’s Paris climate agreement. The significance of which, means an inevitable impact to our health causing more allergies and asthma in the population.
1. Making the Connection: Climate Changes Allergies and Asthma. https://www.apha.org/events-and-meetings/apha-calendar/webinar-events/2016/climate-changes-allergies-and-asthma
2. D’Amato, G., Vitale, C., De Martino, A., Viegi, G., Lanza, M., Molino, A D’Amato, M. (2015). Effects on asthma and respiratory allergy of Climate change and air pollution. Multidisciplinary Respiratory Medicine, 10, 39. http://doi.org/10.1186/s40248-015-0036-x
3. The world passes 400ppm carbon dioxide threshold permanently. https://www.theguardian.com/environment/2016/sep/28/the-world-passes-400ppm-carbon-dioxide-threshold-permanently
Image source: https://www.whitehouse.gov/blog/2016/04/05/get-facts-how-climate-change-can-affect-your-health