Dr. David Jeffrey of Dual Science Solutions (DSS), has extensive experience teaching and tutoring non-native English speaking students in chemistry and environmental science. Dr. Jeffrey has worked with students from the following countries and locations:


  • China (PRC)

  • Hong Kong

  • Indonesia

  • Iran

  • Malaysia

  • Philippines

  • Serbia

  • South Korea

  • Spain

  • Taiwan

  • Thailand

  • Vietnam

DSS provides tutoring services to students outside the United States, but all instruction is in English.


When working with students outside the U.S., DSS will convert its Schedule of Rates from USD to the necessary currency, using

DSS uses the currency converter features of PayPal for Business to accept payments in any of the following currencies.  

The following are the accepted currencies and the approximate rates for one hour of individual high school chemistry tutoring:


  • Australian dollar AUD 

  • Brazilian real BRL 

  • Canadian dollar CAD 

  • Czech koruna CZK 

  • Danish krone DKK 

  • Euro EUR 

  • Hong Kong dollar HKD 

  • Hungarian forint HUF 

  • Indian rupee INR 

  • Israeli new shekel ILS 

  • Japanese yen JPY 

  • Malaysian ringgit MYR 

  • Mexican peso MXN 

  • New Taiwan dollar TWD 

  • New Zealand dollar NZD 

  • Norwegian krone NOK 

  • Philippine peso PHP 

  • Polish złoty PLN 

  • Pound sterling GBP 

  • Russian ruble RUB 

  • Singapore dollar SGD 

  • Swedish krona SEK 

  • Swiss franc CHF 

  • Thai baht THB 

  • United States dollar USD