Fog weather5/9/2023 ![]() The air quality is good when the AQI value ranges from 51 to 100. Everyone can take part in the outdoor activities and enjoy a breath of fresh air. The air quality is excellent when the AQI value range is between 0 and 50. Pay attention to the Air Quality Index (Air Quality Index, referred to as AQI) issued by the environmental protection department. Thus, it’s not advised for people to go out, let alone to do some excise in the fog and haze weather aerobic exercise indoors is advised. The fog and haze can cause low visibility and increase the occurrences of traffic accidents. Therefore, we should avoid the outdoor activities in the fog and haze if possible. The low temperature stimuli in the morning may more easily induce acute onset of chronic respiratory or cardiovascular diseases in the elderly. The fog and haze can increase the air humidity and decrease the oxygen level. ![]() Doing some exercise in an oxygen-enriched environment is conducive to health. Plants absorb carbon dioxide and release oxygen. Photosynthesis starts in the good lighting conditions. It might be better not to drive so as to contribute to reduction of exhaust emission. If you have to go out, choose public transportation rather than ride a bike evade traffic jam to avoid inhaling more air pollutants. Patients with respiratory or cardiovascular diseases are proposed to minimize going out to reduce PM2.5 exposure in the fog and haze weather ( 1). But patients with cardiovascular or chronic lung diseases may suffer dyspnea and hypoxia due to a great inspiratory resistance caused by wearing this kind of professional masks ( 10). The use of N95 masks has been recommended in the fog and haze weather. N95 masks filter at least 95% of airborne aerosol with a mass median aerodynamic diameter particle of about 0.3 µm. The National Institute for Occupational Safety and Health (NIOSH) and the Centers for Disease Control and Prevention (CDC) of the United States recommend the use of a NIOSH-certified N95 or better respirator for protection of healthcare workers who come in direct contact with patients with avian virus of H1N1. Respirators are used to protect users from hazardous dusts, smoke, carbon monoxide and other particles. Sufficient vitamin intake is helpful to mitigate the adverse effects of the fog and haze. Liver and seafood also provide zinc, selenium, copper and other trace elements, maintaining the function of the immune system. It can be replenished by eating fresh vegetables and fruits ( 5). Vitamin C is a highly effective antioxidant, acting to lessen oxidative stress, which exerts a positive impact on cardiovascular disease, hypertension, chronic inflammatory diseases, diabetes and severe burns. Vitamin D is found in a few dietary sources, such as cod liver oil, fatty fish species, including catfish, salmon, and mackerel ( 6). Its deficiency can cause rickets, osteoporosis, osteomalacia, tetany disease and viral infections due to lack of sunlight exposure. Vitamin D is mainly synthesized in adequate amount by the skin exposed to sunlight. vitamin A is found naturally in cod liver oil, liver, dandelion greens, carrot, eggs, milk and fruits ( 5). Manifestations of vitamin A deficiency are impaired vision and immunity. This results in condensation of water vapour into droplets and hence formation of fog.Vitamin A raises the body’s immune functions and improves resistance to infections. During this time, as the water near the coast is still rather cold, the warm and humid air may be cooled sufficiently by the underlying cold water. As cold air from the north recedes, warm and humid air comes in from the sea. ![]() In springtime, Hong Kong and neighbour areas are affected by alternate cold and warm air. ![]() What causes the fog commonly seen in springtime? In Hong Kong, mist is said to have formed when the visibility falls between 1 to 5 km. Different places in the world use slightly different definitions. For mist, there is no uniform definition at present. What is the difference between fog and mist?Īccording to the World Meteorological Organization, fog is said to have occurred when the visibility is reduced to less than 1 km by water droplets suspended in the air. In Hong Kong, fog is common in springtime between February and April. These droplets reduce the visibility near ground level. Under light wind, stable and humid conditions, if the air near the ground cools down sufficiently, water vapour in the air may condense into tiny water droplets. In Hong Kong, fog is common in springtime and may greatly affect shipping and aviation. Fog is made up of a large amount of tiny suspended water droplets near the ground.
0 Comments
Leave a Reply. |