On some weekends during the Shanghai World Expo there were over a million people visiting the area in a single day. Imagine the plants needed to clean the air above the expo? Imagine the amount of work needed to clean the Huangpu after the night sweepers dutifully sweep remaining residue into the river. While Shanghai has come a long way in terms of cleanliness, sanitation and fighting pollution, there are naturally still remnants of old habits and poor air and water quality, as there are in most major cities.
To combat the poor air quality, especially in winter when trees and other air-cleaning plants are leafless, you can purchase indoor houseplants to clean the air in your home. Humidifiers are good for adding moisture to the air during winter, and combined with a few plants your air quality should go right up! Even if you are staying at a hotel for a short term, plants are easy to find around town, cheap, and do the trick.
Face masks are common in Shanghai and you’ll often see people on the subway and buses wearing them to keep from inhaling excesses of exhaust or from getting sick, especially during flu season. Locals wear gloves on public transportation and travelers use hand sanitizer religiously, both of which are helpful when traveling.
Avoid drinking the water in Shanghai unless bottled. Brushing your teeth at night in the tap water is okay, but if you are only visiting for a short time why risk getting ill? Bottled water is cheap, readily available and smart for someone who isn’t staying long and doesn’t need to get accustomed to the common metals/bacteria in the water.
Finally, rush hour can be a harrowing traveling time in Shanghai, avoid it to avoid stress and increases in pollution from the traffic. Most sights in the city are less busy midday and thus easier to see anyway.