Spotters in "Environment and Health: Air" for CFM & MPH students

 Air direction:

1. Wind vane/ Wheather vane/ Wheathercock:

Important points:

• It is an instrument used for showing the direction of the wind.
• When the wind is sufficiently strong, the head of the arrow or cockerel indicates the direction from which the wind is blowing.
• The wind vane is placed high enough to avoid wind interference from objects, buildings, and trees like the top of towers, poles, etc.
• Types-Weathervane, Wind Sock, Digital Wind Vane
• Benefits: Safety from storms, very helpful in activities like golf and boat sailing.

Air speed:

2. Anemometer:

Important points:

• It is a device used for measuring wind speed, direction & pressure.
• A common weather station instrument.
• Types- Cup, Vane, Hot-wire, Lesser doppler, Ultrasonic, Pin-pong ball, Plate & Tube anemometer
• Uses: helps indicate a change in weather patterns, such as an approaching storm, which is important for pilots, engineers, and climatologists.

Air/ Atmospheric pressure:

3. Aneroid barometer:

Important points:

• It is an instrument for measuring air pressure as a method that does not involve liquid.
• It uses a small, flexible metal box called an aneroid cell (capsule), which is made from an alloy of beryllium and copper.
• Uses: Common in homes and in recreational boats but also used in meteorology, mostly as barograph and pressure instruments in radiosondes for detecting any changes in the atmospheric pressure. 
• More useful in field but requires constant calibration. 

4. Mercury barometer:

Important points:

• The mercury barometer's design gives rise to the expression of atmospheric pressure in inches or millimeters of mercury (mmHg).
• It has a vertical glass tube closed at the top sitting in an open mercury-filled basin at the bottom. Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir.
• It is more accurate than Aneroid barometer.

Air Humidity:

5. Mason's hygrometer:

Important points:

• A standard hygrometer using the wet bulb and dry bulb method to determine air humidity & air temperature.  
• Two red liquid-filled thermometers are secured to the plastic scale plates.  
• Used at most of the meteorological stations. 

6. Sling/ Whirling psychrometer:

Important points:

• It is an instrument that measures the relative humidity and dew point in an area. 
•  It has two thermometers: a wet bulb and a dry bulb.
• It works on the premise that evaporation is a cooling process. The drier the air, the more evaporation takes place off of the wet bulb, dropping the temperature on the thermometer.
• Uses:  For checking humidity level in air-conditioned rooms and installations, to set and check hair hygrometer, in the measurement range of 0 to 100% RH & for measuring wet bulb temperature between 0’C to 180’C.

7. Assman's/ Aspirator psychrometer:

Important points:

• It serves for measuring the air temperature and the humidity. 
• Two parallel mounted, equal thermometers with colored petroleum are used.
•  The dry bulb thermometer is indicating the true air temperature. 
• The difference in temperature of both thermometers results in the psychrometric depression. 
• From this, the relative humidity, the dew point temperature, and the vapor pressure of the air may be computed or determined from tables.

8. Electrical hygrometers:

Important points:

• It helps to measure humidity or dewpoint or managing humidity control.
• It measures the change in electrical resistance of a thin layer of lithium chloride, or of a semiconductor device, as the humidity changes. 
• Other hygrometers sense changes in weight, volume, or transparency of various substances that react to humidity.

Air pollution:

9. Air quality index:

Important points:

• It is an index for reporting air quality on a daily basis.
• It has six categories with the element color scheme which is decided by ambient concentration values of air pollutants & their likely health impacts (breakpoints)
• Objectives- Comparing air quality conditions at different locations/cities, helps in identifying faulty standards and inadequate monitoring programs, helps in analyzing the change in air quality (improvement or degradation) &  informs the public about environmental conditions. 

References:

1. Park, K. (2019). Park's textbook of preventive and social medicine. 25th. Jabalpur, India: M/S Banarsidas Bhanot.
2. Kadri AM. (2019). IAPSM's Textbook of Community Medicine. 1st. New Delhi, India: Jaypee Brothers Medical Publishers (P) Ltd.
3. https://www.newconceptlouvers.com/weather-vanes/proud-rooster-weather-vane photo credit
4. https://videohive.net/item/wind-gauge-at-the-airport/21162667 photo credit
5. https://www.fishersci.com/shop/products/aneroid-barometer/13300176 photo credit
6. https://utsic.utoronto.ca/wpm_instrument/mercury-manometer/ photo credit
7. https://www.sciencesource.com/archive/Mason-s-Hygrometer-SS2586031.html photo credit
8. https://sites.google.com/site/msswcgi/the-inquiry-cycle/step-2-collecting-data/measuring-relative-humidity-sling-psychrometer photo credit
9. https://swachhindia.ndtv.com/air-pollution-what-is-air-quality-index-how-is-it-measured-and-its-health-impact-40387/ photo credit
10. https://www.eiscolabs.com/products/ph0245s photo credit
11. https://www.findel-international.com/product/science/environmental-science/meteorology/mini-anemometer/e8r07120 photo credit
12. http://www.extech.com/categories/humidity-meters/ photo credit